Foraging cues

A second approach is to use macerated prey flesh or chemical extracts of prey as the stimulus. This, however, has the disadvantage of releasing cues to the 

Although assays that use whole organisms are perhaps the most ecologically realistic, it would be difficult to isolate the chemical cue(s) or mechanisms responsible for the observed behavior in this assay. As with any ecological study, there are trade-offs between realism and ability to manipulate the system, and combinations of approaches using whole organisms in ecologically realistic set- 

Because invertebrates are easy to manipulate experimentally and have relatively simple nervous systems, invertebrates (particularly decapod crustaceans and gastropod mollusks) have been the subject of far more research on chemically mediated foraging than vertebrates. As with vertebrates, many workers have taken the approach of delivering a stimulus in a single pulse of odor injected into standing water by a syringe or pipette, and the behavioral response is compared to that for a control injection of water. For crustaceans, this response 

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Nevitt GA, Veit RR, Kareiva P (1995) Dimethyl sulfide as a foraging cue for Antarctic Procellariiform seabirds. Nature 376 680-682... 

More simultaneous measurements of NH3 in the ocean and in the atmosphere are needed to reduce the considerable uncertainties of the ocean/atmosphere flux estimates. The ongoing acidification of the ocean will shift the NH3/NH4 equilibrium to NH. On the one hand this might have implication for the atmospheric distribution of NH3, since the uptake capacity of the ocean will be increased with unknown consequences for chemistry of the atmosphere (e.g. the aerosol formation) over the ocean. On the other hand this might have severe implications for the nitrification rates in seawater because they are influenced by the pH. When the pH drops from 8 to 7, nitrification rates can be reduced by 50% (Huesemann et al., 2002). (One explanation for this is that the ammonia monooxygenase enzyme uses rather NH3 than NH4 as substrate.) Most recently it was suggested that atmospheric NH3 serves as a foraging cue for seabirds such as the blue petrel (Nevitt ei a/., 2006) is an excretion product of... 

Just as chemical cues from prey are used as foraging cues by predators, prey also use chemical cues as a warning that predators are near or that conspecifics... 

Tetratrophic interactions between a host plant, a phytophagous pest (primary host), a hymenopteran parasitoid or symbiont (secondary host) and a hymenopteran hyperparasitoid (which parasitizes the secondary host) are of considerable importance, because hyperparasitism can significantly reduce populations of economically beneficial parasitoids [11]. Hyperparasitoids use host-marking (=spacing) pheromones, sex pheromones [12], and host-detection cues [42], but they also show additional chemically mediated interactions with the other partners. These include detection of the primary host s secretions by the hyperparasitoid [43], detection of plant volatiles by the hyperparasitoid [44], and detection of the hyperparasitoid s secretions by the primary host [45] or by the secondary host. The latter causes the secondary host to avoid locations where the hyperparasitoid is foraging [46]. 

Traversing a maze in which no proximate odor cues are present, but in which snakes have previously received rewards was here defined as a foraging task. Such a task permits one to analyze tongue-flick patterns before and after prey consumption. 

Interspecific chemical cues are also often mixtures. Mixtures of amino acids serve as feeding stimulants in fish. Among mammals, ferrets respond more to mixtures than to pure odors in their foraging responses. The mixtures are thought to contain more information (Apfelbach, 1973). 

Visual and chemical cues interact in foraging by natricine snakes. Even visual cues alone can elicit prey attack, especially in aquatic foraging (Drummond, 1985). Aposematic color patterns of prey enhance the learning of prey that induces illness. Garter snakes, Thamnophis radix hay deni, were exposed to fish and earthworms presented on black-and-yellow forceps, and then inj ected with lithium chloride (LiCl). Control prey was offered on green forceps. Later, the snakes avoided food from either forceps, but the aversion to prey paired with black-andyellow was stronger (Terrick etal, 1995). 

Chiszar, D., Kandler, K., Lee, R., and Smith, H. M. (1988b). Stimulus control of predatory attack in the brown tree snake, Boiga irregularis. 2. Use of chemical cues during foraging. Ampfete-RepftZw 9,77-88. 

Vadas, R.L., Burrows, M.T., and Hughes, R.N., Foraging strategies of dogwhelks, Nucella lapillus (L.) interacting effects of age, diet and chemical cues to the threat of predation, Oecologia, 100, 439, 1994. 

Chemically mediated interactions have important direct and indirect effects on communities from both ecological and evolutionary standpoints.22 341 Chemical defense or communication cannot be properly understood unless it is viewed through the lenses of population, community, and ecosystem processes, and this requires consideration of both the biotic and abiotic components of the natural environment.342 For example, chemically mediated foraging is affected by water flow because it relies on water-soluble cues that are carried away from prey.343 345 Similar constraints likewise modify the effectiveness of other waterborne cues, such as alarm signals, sexual pheromones, and settlement cues, in both mobile and sessile organisms.244 345 350... 

Giurfa M. (1993) The repellent scent-mark of the honeybee Apis mellifera ligustica and its role as communication cue during foraging. Insect. Soc. 40(1), 59-67. 

Figure 12.1 Harvester ant foragers are stimulated to leave the nest in search of seeds in response to cues present in the task-specific cuticular hydrocarbon profile of patrollers. After inhibition of foragers at harvester ant colonies by removal of patrollers, colony foraging behavior was rescued by the addition of ant mimics, glass beads coated with task-specific cuticular hydrocarbons from patrollers, to the nest entrance at a rate of 1 bead every 10 seconds. Data were normalized to account for differences in the absolute number of foragers active each day. The same letters above bars denote statistical significance using a Tukey s post-hoc test. From Greene and Gordon, 2003.

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